Patent GB-1481876-A (GB)
Title: Friction-surface sheet
IPC: B32B27/00
Filed: 1974-10-04
Abstract: 1481876 Embossed adhesive sheets MIN NESOTA MINING & MFG CO 4 Oct 1974 [5 Oct 1973] 43176/74 Heading B2E [Also in Division B5] A friction surface sheet comprises a heat set biaxially oriented polyethylene terephthalate support having an embossed coating on one side of a flexible ethylenic copolymer material and on the other side a coating of a pressure sensitive adhesive. A primer layer may be present on each side of the support. In a preferred method of making the sheet, Fig. 1, the polyethylene terpehthalate backing is primed by application of a molten sheet 13a of a U.V. transmitting thermoplastic polymer and subjected to U.V. radiation by a lamp 15 to bond it to the polymer. A molten sheet 18a of the ethylenic copolymer material is then applied to the primer layer and cooled by passage through rollers 19 and 20, the roller 20 also embossing the copolymer. After treatment with a decuring edge a natural rubber solution primer 28 is applied to the other side of the backing by reverse roll, dried at 31 and irradiated with a U.V. lamp 33. The rubber primer is then transfer coated with a layer of pressure sensitive adhesive which has previously been coated onto a release layer. The coated sheet is then consolidated between rollers 40 and 41, before stripping the release sheet. In Examples: (1) a support sheet of heat set, biaxially oriented polyethylene terephthalate is primed by melt extruding with ethylene/ethyl acrylate copolymer and the primer melt extrusion coated with a blend of ethylene/ethyl acrylate copolymer (82/18), predispersed TiO 2  in l.d. polyethylene, "VANCITE" (registered Trade Mark) bacteriostat and a U.V. absorber, before embossing the copolymer and coating the other side of the base with natural rubber primer then an adhesive composition which is a mixture of (A) a composition comprising crude rubber, ZnO, lanolin, natural pine rosin, phenol/aldehyde resin, tackifier and solvents and (B) a composition comprising pale crepe rubber, polyterpene resin, zinc resinate, phenolic tackifier, C black, TiO 2 , solvent, antioxidant and tricresyl phosphate; (2) as in (1) except that the adhesive comprises an AB block copolymer (polystyrene-polyisoprene), petroleum resin tackifier, antioxidant and TiO 2 ; (3) as in (2) except that polymer of the adhesive comprises the AB block copolymer and a multiblock copolymer; (4) as in (2) but using a multiblock copolymer; (5) as in (1) but using an acrylic acid/isooctyl acrylate (10:90) copolymer adhesive as in Example 7 of U.S. Patent Re 24906; (6) as in (1) except a primer for the embossed layer containing ethylene/vinyl acetate copolymer is used; (7) the base sheet is formed by coextruding layers of polyethylene terephthalate and a thermoplastic polyester, the thermoplastic polyester taking an embossed layer of ethylene/ethyl acrylate copolymer and the polyethylene terephthalate being coated with primer and adhesive as in (1); (8) the base sheet of (I) was extrusion coated with polyethylene primer, then with ethylene/propylene/diene terpolymer and embossed, the adhesive being that of composition (B) in (1) arid the primer for the adhesive being as in (1); (9) as in (1) using ethylene/vinyl acetate copolymer as the embossed layer; and (10) as in (1) except that the embossed layer comprises a composition of ethylene/vinyl acetate, powdered polyethylene and shredded scrap rubber tyre as filler.